Light fixtures provide a source of light to illuminate dark environments. A light fixture, or luminaire, can be constructed from a light source placed in contact with a cover directing light from the light source into an environment. In some cases, the cover of a luminaire can include particular optical properties for directing the light emitted by the luminaire. For example, the cover can include a diffuser for changing the radiation pattern of light provided by the light source within the luminaire. Some luminaires, however, can be placed in environments where a standard light pattern may be inefficient or lead to undesirable lighting artifacts. Alternatively, the cover can be substantially co-planar with a drop ceiling, and be a source of glare.